Fossil fuel is a general term for buried combustible geologic deposits of organic materials formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust over hundreds of millions of years. Fossil fuels are a finite, non-renewable resource.
Increased demand for energy by the global economy has also placed increasing pressure on the cost of hydrocarbons. Aside from energy, many industries, including plastics and chemical manufacturers, rely heavily on the availability of hydrocarbons as a feedstock for their manufacturing processes. Cost-effective alternatives to current sources of supply could help mitigate the upward pressure on energy and these raw material costs. Major efforts to this end are focused on the microbial production of high-energy fuels by cost-effective consolidated bioprocesses. However, some alternatives to fossils fuels production, such as fermentation-based approaches for generating combustible products rely on the use of a large quantity of carbohydrate-rich feedstock such as sugar cane, rice, corn, or the like. Use of such resources to produce combustible fuel has the undesirable consequence of increasing the market pressures on feed stocks, driving up the price of the world's food supply.
Fatty acids are composed of long alkyl chains and represent nature's petroleum, being a primary metabolite used by cells for both chemical and energy storage functions. These energy-rich molecules are today isolated from plant and animal oils for a diverse set of products ranging from fuels to oleochemicals. A more scalable, controllable and economical route to this important class of chemicals would be beneficial to the development of renewable energy sources.